1. Field of the Invention
The present invention relates to a printing apparatus capable of printing on a plurality of rolls of paper each fed through a different conveyance path. Specifically, the invention relates to a method of detecting information concerning a newly mounted roll of paper even when another roll of paper is being conveyed without suspending the conveyance operation.
2. Description of the Related Art
Some printing apparatuses which performs printing on a continuous sheet wound in a roll-shape (hereinafter, referred to as roll of paper) are designed to mount a plurality of rolls of paper the type and/or size of which are different from each other. In such a printing apparatus, printing of an image is selectively carried out on either one of the rolls of paper. These rolls of paper are fed out through a different conveyance path respectively, and then into a common conveyance path. The printing is carried out on the roll of paper in the common conveyance path. Before carrying out the printing of an image, the printing apparatus has to obtain information concerning type, size or the like of the roll of paper to be printed. Conventionally, there are known as the obtaining methods, a method in which information is input by a user using an inputting means, or a method in which the information is obtained by a sensor provided on a printing apparatus.
For example, Japanese Patent Publication No. 02848062 discloses, in the specification thereof, an arrangement in which, every time a new roll of paper is mounted, the size of the paper is recognized based on both of information input by a user and detection result by a sensor disposed within a common conveyance path for a plurality of rolls of paper.
However, according to the apparatus described in the specification of Japanese Patent Publication No. 02848062, the roll of paper is conveyed into a common conveyance path, and the size of the paper is detected by the sensor disposed on the common conveyance path. Therefore, during printing on one roll of paper or conveying thereof, the size of another roll of paper cannot be detected. That is, when a new roll of paper is mounted during printing on a roll of paper, the information concerning the newly mounted roll of paper cannot be obtained until the printing on the other roll of paper is completed. Since the information of the new roll of paper is obtained after the printing on the proceeding roll of paper has completed, a certain time is required for conveying the new roll of paper and detecting information thereof, and thus the user has to wait for the completion of the conveyance and detection.